Internal combustion engine



April 5, 1932. L WQQLSQN 1,852,498

' INTERNAL COMBUSTION ENGINE Filed June 25, 1928 2 Sheets-Sheet lgwvwntoz LJCINEL M Nam: sum.

April 5, 1932- L. M. wooLoN 9 INTERNAL COMBUSTION ENGINE Filed June 25,1928 2 Sheets-Sheet 2 5 A W E.

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Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE LIONEL M. WOOLSON, OFDETROIT, MICHIGAN, ASSIGNOR TO PACKARD MOTOR CAR COMPANY, OF DETROIT,MICHIGAN, A CORPORATION OF MICHIGAN INTERNAL COMBUSTION ENGINEApplication filed June 25,

This invention relates to internal combustion engines.

The principal object of this invention is to provide improved means forsecuring the cylinders to the crank case of engines of the ra dial,opposed cylinder or related types. More particularly tension band meansencircling the crank case in close proximity thereto are provided tofasten the cylinders to the crank case.

Heretofore in internal combustion engines, particularly engines of theradial, opposed cylinder and related types, where the cylinders of theengine are generally separately formed, bolts or similar threadedfastening means have usually been employed for securing the cylindersindividually to the engine crank case. With this method of fastening thecylinders to the crank case, however, the stresses communicated from thecylinders during operation of the engine, subject the crank case torecurring tensile loads that are more or less concentrated within anarea roughly defined by the fastening means of each cylinder. Whileusually satisfactory for engines having a relatively low compressionratio, such as carburetion engines, this method of securing thecylinders to the crank,

case has not generally proven satisfactory for engines having arelatively high compression ratio, where the explosive pressures withinthe cylinders are relatively very high, as in compression-ignition orsolid fuel injection engines, unless the crank case is made undesirablyheavy to withstand the relatively high tensile stresses referred to.But, where the ratio of the weight of the engine to the power developedthereby is of prime importance, as in aircraft engines, any unnecessaryincrease in the weight of the engine parts is to be avoided.

The band means of the present invention eliminates the usual fasteningbolts or similar threaded means and absorbs the recurring tensile loadsresulting from the expansion of the explosive mixture during operationof the engine thus relievin the crank case of these relative hightensile stresses to which it would be subjected were bolts used. Theseloads are distributed uniformly around the 1928. Serial No. 287,963.

crank case which is sion by the band means.

Two bands one on each side of the cylinders are employed and they engagearcuate surfaces on flanges which are rigid with the cylinders and seaton the crank case. placing the bands adjacent or in close proximity tothe crank case several important advantages are attained among which maybe mentioned here the following: The bands are of minimum'length andweight. They create practically no wind resistance. The cylinders may bemade light in weight as the bands impose no stresses on them. Theflanges on the cylinders are held uniformly against their seats on thecrank case thus maintaining the cylinders in exact radial alignment andeliminating localized stresses on the flanges.

Another object of this invention is to form the tension bands insections and connect the same by adjustable means which permit the bandsto be properly tensioned and also afford ready assembly and disassemblyof the cylinders and crank case.

Other objects of the invention will appear from the followingdescription taken in connection with the drawings forming a part of thisspecification, in which:

Fig. 1 is a front elevation, with parts broken away, of an internalcombustion engine embodying the present invention;

Fig. 2 is a sectional view of the engine, wfitip parts broken away,taken on line 2-2 0 ig. 1;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a sectional view taken on line 44 of Fig. 3;

Fig. 5 is a sectional view taken on line 55 of Fig. 3, and

Fig. 6 is a sectional view taken on line 6-6 of Fi 3.

Referring to the drawings, 10 represents generally a nine cylinderradial internal combustion engine of the compression-ignition or solidfuel injection type embodying the present invention. As shown, theengine has a crank case 11 of substantially cyllndrical form, providedwith an integral diaphragm placed under compres- 12 and a removablediaphragm 13 secured by suitable means on the inside of the crank case.Mounted in suitable bearings in the diaphragms 12 and 13 is a crankshaft 1 1, having a crank 15 upon which are journalled connecting rods16 connecting the pistons of the engine to the crank shaft. Thediaphragms define a plurality of relatively isolated compartments in thecrank case, the central one of which houses the crank and rods. Aremovable cover 17 secured in position by any suitable means closes theopen anti-propeller end of the crank case, the cover being provided withan opening 18 through which the driving shaft of the engine starter, notshown, projects. A propeller hub 19 is non-rotatably secured in anysuitable manner on the forward end of the crank shaft.

In the form shown, the engine has separately formed cylinders 20, eachprovided with a laterally projecting flange 21 adjacent its lower openend. The flange 21 is provided, on the side facing the cylinder head,.With opposed, relatively elongated, preferably arcuate grooves 22, asbest shown in Figs. 1 and 4, and is also provided with opposedprojecting portions 23, preferably located between the opposed arcuategrooves 22. The circumferential part of the crank case is provided withspaced openings 24. adapted to receive the projecting ends 25 of thecylinders and surrounding or adjacent each of these openings 24, thecrank case is preferably flat to provide a plane seat 26 for thecylinder flanges 21.

As shown, the cylinders are removably secured in radial position on thecrank case by two continuous bands 27 of preferably circular crosssection positioned in the grooves 22 of each cylinder flange andextending around the crank case. Each of the bands 27 is preferablyformed in three sections, as shown, the ends of the sections beingthreaded and connected by suitable turnbuckles 28. The portions of thebands 27 adapted to be positioned in the cylinder flange grooves 22 arepreferably arcuately formed to correspond with the curvature of thegrooves 22, and those portions adapted to be positioned between thecylinder flanges 21 are preferably formed straight, as shown.

In order to retain the cylinders in position on the crank case duringassembly of the engine or during removal and repair of one or more ofthe cylinders, an auxiliary fastening means for the cylinders isemployed. This auxiliary fastening means comprises lugs 29 adapted toengage the projecting portions 23 of adjacent cylinders and to beremovably secured in position by bolts 30 or other suitable meansengaging the crank case.

In assembling the engine, after the cylinders have been mounted on thecrank case and the lugs 29 secured in position in engagement with theprojecting portions 23 of the cylinder flanges, the bands 27, thesections of which have previously been connected by the turnbuckles 28,are slipped over the cylinder flanges 21, into the flange grooves 22,after which the turnbuckles are rotated to contract or tighten the bandsabout the cylinder flanges and thus securely hold the cylinders inposition on the crank case. To remove the cylinders, the turnbuckles arerotated in the opposite direction to expand or loosen the bandssufliciently to permit them to be slipped off the cylinder flanges.

The diaphragms 12 and 13 are preferably so located or positioned in thecrank case that their peripheries will lie in the plane of the bands 27when in position, although it will be apparent that they may bepositioned at one side or the other of the planes of the hands ifdesired. The bands, when in position and tightened or contracted aboutthe cylinder flanges, preferably engage the cylinder flanges only, andare entirely out of contact with the crank case, as shown. It will thusbe apparent that the bands form a securing means totally independent ofthe crank case for securing the engine cylinders thereto.

With this method of securing the cylinders to the crank case, it will beclear that as the bands are tightened or contracted about the cylinderflange and the crank cane, compressive stresses will be set up in thecrank case, or, in other words, the crank case will be compressed, asthe bands press the flanges against the crank case which acts as a base.The bands are preferably tightened about the crank case until thetension in the bands is considerably greater than any pressure that maybe developed in the cylinders due to the expansion of the explosivemixture after combustion in order to hold the cylinder flanges 21against their seats on the crank case under all conditions and with thedesired factor of safety. In this manner, the crank case is entirelyrelieved of any tensile stress resulting from the expansion of theexplosive mixture in the engine cylinders during operation of theengine, as the tendency of the explosive forces to move the cylindersradially outwardly is not transmitted to the crank case as would be thecase with bolts securing the cylinders in place. i

It will be further seen that the compression bands serve to absorb loadsfrom the cylinders and to distribute them uniformly around the crankcase, such cylinder loads being caused during engine operation, andresulting principally from explosion forces in the cylinders, sidethrust of the pistons on the cylinders, and vibration.

The diaphragms 12 and 13 serve to reinforce the casing, and also toprovide partitions which divide the easing into a plurality of isolatedcompartments. This manner of forming compartments lends to compactnessand ruggedness of an engine casing, while the bands andthe associationtherewith of the diaphragms permit the casing wall to be formedrelatively thin and at the same time rugged enough to withstand the highpressures developed by engines of the compression-ignition or solid fuelinjection type. Furthermore, this construction of a relatively lightcasing makes it possible to successful ly use compression-ignition orsolid fuel injection engines with aircraft. Thus the Weight-power ratioof a high compression ratio engine need not, necessarily, be materiallygreater than that of a low compression ratio engine. In the engineshown, it has been found that the crank case may satisfactorily be analuminum casting and the removable diaphragm may be of duralumin.

While the present invention is shown and described as embodied in aradial engine of the compression-ignition or solid fuel injection type,it will be apparent that the invention may readily be adapted to othertypes of engines, if desired.

The form of the invention shown and described is to be considered as apreferred form only and it is to be understood that the invention is tobe limited only by the scope of the appended claims.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. In an internal combustion engine, in combination, a crank case, aplurality of cylinders, each of the cylinders having a flange providedwith a plurality of grooves, said flange bearing against the crank case,and means comprising a pair of continuous bands in tension surroundingthe crank case and engaging the grooves in the cylinder flanges, saidbands tensionally securing the cylinders to the crank case anddistributing cylinder loads to the crank case and being in tensiongreater than that which is developed therein by the maximum explosiveforce developed in any cylinder.

2. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, flanges on thecylinders and bearing against the crank case, and a pair of tensionbands encircling the flanges on opposite sides of the cylinders andsecuring them against the crank case, said bands being placed in tensiongreater than that which is developed therein by the maxinum explosionforce developed in any cylinder.

3. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, flanges rigid with thecylinders and bearing against the crank case, said flanges havingarcuately extending grooves in their outer faces arranged in circularrelation on opposite sides of the cylinders, and a pair of tension bandssurrounding and seated in the grooves in the flanges, said bands beinsecured in tension greater than that which 1s developed therein by themaximum explosion force developed in any cylinder.

4. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, and cylinder securingmeans closely encircling and compressing the crank case and engaging thecylinders adjacent thereto, said means being in tension in excess ofthat which is developed therein by the maximum explosive force developedin any cylinder.

5. In an internal combustion engine having a crank case and cylinders,tension means for securing the cylinders to the crank case comprisingremovable contracted band means encircling the crank case and engagingthe cylinders adjacent that part bearing against the crank case, saidband means being in tension in excess of that which is developed thereinby the maximum explosive force developed in any cylinder.

6. In a radial internal combustion engine, a crank case; a plurality ofcylinders and means securing the cylinders to the crank case includingcylinder flanges bearing against the crank case and circular members intension engaging the flanges, said securing means distributingsubstantially all forces developed in any cylinder during engineoperation around the crank case and holding each flange in uniformbearing contact with the crank case.

7. In an engine, a substantially cylindrical crank case, cylindersbearing against the crank case and extending radlally from the crankcase, band means surrounding the crank case and engaging the cylindersadjacent the crank case, and reinforcing walls within the crank casesubstantially in the same plane with the band means, said band meansbeing in tension greater than that which is developed therein by themaximum explosion force developed in any cylinder.

8. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, flanges connected tothe cylinders and bearing against the crank case, and-a pair of tensionbands, including sections and adjustable connecting means therebetween,encircling the flanges on opposite sides of the cylinders and securingthem against the crank case, said bands being placed in tension greaterthan that which is developed therein by the maximum explosion forcedeveloped in any cylinder.

9. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, flanges rigid with thecylinders and having arcuate surfaces, and a pair of tension bandshaving alternate arcuate and straight portions with the arcuate portionsseated on said arcuate surfaces, the bands being secured in tensiongreater than that which is developed therein by the maximum explosionforce developed in any cylinder.

10. In an internal combustion engine, a crank case, a plurality ofcylinders extending radially from the crank case, and means includingbands in close proximity to and compressing the crank case and connectedWith the cylinders adjacent thereto to secure the cylinders against thecrank case, said bands being in tension in excess of that which isdeveloped therein by the maximum explosive force developed in anycylinder.

In testimony whereof I afiix my signature.

LIONEL M. WOOLSON.

